Ability to customize easy-to-service parts
This idea is simple: in Outlet systems, allow people to customize the easy-to-service parts of Dell/Alienware computers. For example, suppose that the following system is available on the Outlet:
nVidia GT 540M
4 GB RAM
500 GB HDD (7200 rpm)
+ other specs (color, etc)
Suppose that I want this exact system but I would prefer to have an SSD. Dell's outlet website should allow this upgrade (at a cost, of course!). If Dell wants, they can allow only upgrades (i.e. replacing stuff in the laptop for something better, such as upgrading from 4 GB to 8 GB of RAM), but disallow downgrades (such as downgrading from 4 GB to 2 GB of RAM).
Only easy upgrades (memory, hard drive, optical drive, battery if it isn't integrated) would be allowed on the Outlet systems. Dell can even only ship the parts to the user and ask him to do the upgrade himself, thus saving labor costs. Upgrades that are trickier (CPU, GPU, screen, color) are not allowed on Outlet systems. The idea here is that the components that are replaced are perfectly re-usable by Dell, and people would be able to combine Dell's trademark customization and excellent warranty with the Outlet's low price.
The buying guide, then, could have an interface which is very similar to Dell's current website for new systems, except that some upgrades (such as CPU, screen, etc) are not allowed. This would be combined with your own suggestion of having a search engine which allows people to easily find systems which match their preferences.